A common problem in the production of various types of crops is that of mineral deficiencies. The overuse of land used to grow crops, along with various growing conditions, can cause a lack of bio-available essential metal ions, often resulting in unhealthy plants. Plants suffering from mineral deficiencies do not grow efficiently, and therefore, the agricultural yields are often decreased.
In an attempt to raise the levels of metal ions in the crops, mineral supplements are often added to the soil. Examples of such mineral supplements include metal oxides, metal sulfates and metal chelates (such as EDTA complexes). Metal oxides and metal sulfates are only effective against metal deficiencies in certain types of soil. Often the metal ions become irreversibly attached to the organic materials in the soil, and therefore, the plants cannot absorb the minerals. Thus, a plant can suffer from mineral deficiencies while growing in a mineral rich soil. Also, metal sulfates and metal chelates can be absorbed too rapidly, causing burning of the plants. EDTA chelates, which are sometimes more effective, are too expensive to be used in many applications.
In addition to the attempts to increase mineral levels in crops through supplements to the soil, aqueous solutions of metal ions have been sprayed directly onto the foliage of the growing plant. By allowing the foliage of the plant to absorb the metal ions directly, the problems encountered with soil and metal ion interactions can be avoided. While some aqueous mineral sprays work adequately, severe burning of the foliage can occur. Such phytotoxicity is particularly prevalent when copper and iron compounds are sprayed onto foliage. The phytotoxicity is believed to be caused by an excessively rapid rate of mineral uptake by the foliage.
Therefore, a need exists for a method to safely, efficiently, and economically provide minerals or other micro-nutrients to plants. A need exists for such a method which includes either spraying the foliage with a nutrient composition or providing the nutrient composition to the soil surrounding the plant. A further need exists for a nutrient composition which releases the nutrients slowly, which is a ready source of bio-available metal ions or other nutrients, and which reduces soil/metal ion interactions.